Ruminant feedstuffs, their production and apparatus for use therein

ABSTRACT

The invention provides novel feedstuffs for ruminants comprising an edible water insoluble salt of an edible higher fatty acid, free fat, excess of the salt-forming metal, and optionally a further nutritional material, expecially a proteinaceous feedstuff such as soya bean meal. Such feedstuffs may be produced by forming a mixture of a basic oxide such as calcium oxide, a mixture of fatty acid and triglycerides, water and optionally the further nutritional material, and allowing the oxide to react with the acid to form the water-insoluble salt. The hot reacting mixture is spread out so that water evaporates spontaneously and a friable product is obtained. The process is operated continuously.

This is a division of application Ser. No. 07/222,889, filed July 18,1988, Pat. No. 4,853,233 which is a division of application Ser. No.06/848,144, filed Apr. 4, 1986, Pat. No. 4,826,694 which is acontinuation-in-part of application Ser. No. 06/721,865, filed Apr. 10,1985, now abandoned.

This invention relates to ruminant feedstuffs, and in particular tofeedstuffs containing edible fatty acid salts, to their production andto apparatus for making the same.

While the processes of fermentation and digestion which take place inthe rumen of ruminant animals are largely beneficial to such animalsunder natural feeding conditions, modern husbandry may require that, foroptimum production of meat and/or milk, such animals should be fed aproportion of their dietary requirements in the form of nutrients whichideally should not undergo any alteration or degradation in the rumen.Also, it is necessary that such nutrients should not interfere with thenormal processes of rumen fermentation.

For example, it is beneficial that a cow should be fed sufficientquantities of fat to maximise her milk production, but it is known thatif a mature cow is fed more than about 500 g of fat per day, the normalprocess of rumen fermentation is adversely affected. Triglycerides andfree fatty acids can physically coat fibrous or cellulosic material inthe rumen and thus prevent it from being broken down by the rumenbacteria. This can have an adverse effect on the total digestability ofthe diet and result in a reduced yield of milk and/or butterfat. Freefatty acids and especially some unsaturated fatty acids are toxic tocertain bacteria in the rumen and this too can have an adverse effect onthe total digestibilty of the diet. In addition, under normalconditions, unsaturated fats fed to ruminant animals are hydrogenated inthe rumen with the result that it is difficult to produce milkcontaining a higher proportion of unsaturated fats. The production ofmilk containing increased amounts of unsaturated fatty acid thusrequires that the fat be protected from normal rumen processes.

In the case of protein metabolism, it is known that at certain periodsduring the growth, development and lactation of cows, insufficientmicrobial protein is produced in the rumen to meet the animals' fullrequirements for maximum growth or maximum milk production. It istherefore desirable that a proportion of the protein requirement of cowsbe met by supplying a supplement containing protein which is notdegraded in the rumen. This can result in an improvement in feedconversion efficiency, growth rate and production as compared with theuse of an equal weight of degradable protein.

There have been a number of proposals of methods for protecting fats andproteins from the effects of rumen fermentation so that they are notdigested until they reach the abomasum or intestine of the ruminant.These methods have for the most part depended upon protecting such fatsand/or proteins (and sometimes other nutritional materials such asminerals or essential vitamins) in a coating which resists thefermentation processes of the rumen.

The present invention provides a feedstuff for ruminants comprising awater-insoluble salt of one or more edible higher fatty acids. Thefeedstuff may contain a further nutritional material, which may be, forexample, a protein, a mineral, or a vitamin.

The ruminant feedstuff of the invention comprises:

(1) 60 to 80%, preferably 70 to 75%, by weight of said feedstuff of amixture of one or more edible, water-insoluble salts especially calciumsalts, of one or more edible, saturated or unsaturated fatty acidscontaining 14, 16 and/or 18 carbon atoms each, with not more than minoramounts of fatty acids containing 12 and/or 20 carbon atoms each, thesaid fatty acid or mixture of fatty acids having an iodine value of lessthan about 60, and a melting point of at least 30° C., preferably above40° C.;

(2) 5 to 15%, preferably 7 to 12% , of extractable triglycerides byweight of said fatty acid or fatty acids;

(3) a metal content corresponding to 9 to 15%, preferably 11 to 14%, byweight of edible metal oxide after calcination at 850° C.;

(4) less than 3%, usually 0.5 to 2%, by weight of unsaponifiable organicmatter; and

(5) up to 10%, usually 3 to 5%, by weight of water.

The ruminant feedstuff of the invention is made by forming a mixture ofcalcium oxide or other edible water-insoluble basic oxide, one or morefatty acids, and water, allowing the calcium (or other) oxide to reactexothermically with the said acid to form the calcium (or otherwater-insoluble) salt thereof, and spreading out the hot, reactingmixture so that sufficient water evaporates spontaneously from themixture to give a friable product. The reaction between the oxide andthe acid normally starts spontaneously with little delay after the waterhas been added, but if necessary the mixture may be heated (before orafter the addition of the water) to ensure that rapid reaction occurs.

More particularly, a ruminant feedstuff of the invention is produced bycontinuously forming a mixture of:

(1) one or more edible, saturated or unsaturated fatty acids containing14, 16 and/or 18 carbon atoms each, with not more than minor amounts offatty acids containing 12 and/or 20 carbon atoms each, the said fattyacid or fatty acids having an iodine value of less than about 60 and amelting point of at least 30° C., and being mixed with triglycerides ofsaid fatty acids and unsaponifiable material in the proportions of 60 to90%, preferably 70 to 80%, by weight of said acids, 40 to 10% by weightof said triglycerides and less than 3% by weight of unsaponifiables;

(2) one or more edible basic oxides capable of forming edible,water-insoluble salts with said fatty acids, the weight of the saidoxide (2) being from 20 to 80% in excess of the weight equivalent of thetotal fatty acids (including fatty acids present as triglycerides) inthe fatty acid mixture (1); and

(3) water in a proportion of 10 to 30%, preferably 18 to 20%, by weightof said fatty acids and triglycerides (1); homogenizing said mixturebefore substantial chemical reaction takes place, continuously spreadingout said mixture at above 60° C. and allowing said mixture to reactexothermically to form water-insoluble salts of said fatty acids; andcontinuously maintaining the reacting mixture in a spread-outconfiguration until it has cooled to below 70° C. and sufficient waterhas evaporated to give a friable product.

Preferably, the fatty acids and triglycerides are first mixed with thebasic oxide, and the water is then added. Alternatively, the fatty acidsand triglycerides, the basic oxide and the water may be mixedsimultaneously. Other possibilities are first to mix the fatty acid andtriglycerides with the water and then to add the oxide, or first to mixpart of the fatty acids and triglycerides with the water and theremainder with the oxide and then to combine the two mixtures.

The process may be operated so that a proteinaceous feedstuff isincorporated in the final product. Thus it can be advantageous toproduce feedstuffs comprising a good quality animal or vegetable proteinsuch as, for example, grass meal, lucerne meal, field beans, peaprotein, coconut meal, cotton seed, ground nut, linseed, palm kernel,soya bean, defatted soya bean meal, sunflower seed, rape seed, fishmeal, meat and bone meal, skim milk, whey protein, distillersby-products, barley, maize, oats, rye, rice, gluten meal, locust bean,canola, feather meal, sorghum, safflower seed, single cell protein, oryeast. All of these materials are suitable, if necessary afterappropriate comminution, for feeding to ruminants to improve the qualityof their protein intake. This aspect of the invention is described belowwith reference to the use of defatted soya bean meal, but it will beunderstood that other proteinaceous feedstuffs can be substitutedtherefor.

The fatty acids used in the invention are edible, saturated orunsaturated fatty acids containing 14, 16 and/or 18 carbon atoms permolecule, preferably stearic acid, myristic acid, palmitic acid, oleicacid, linoleic acid or linolenic acid. It is normally preferred to use anaturally occurring mixture of such fatty acids derived from, forexample, beef or mutton tallow, palm oil, or lard. Such materials areproduced as by-products of edible oil refining. They normally contain,in addition to one or more fatty acids, also a proportion of thecorresponding triglycerides. The presence of such triglycerides isnecessary in the process of the invention to ensure that a satisfactoryproduct is obtained. Beef tallow acid oil and palm acid oil and fattyacid distillates obtained therefrom (which normally include anappropriate proportion of triglycerides) are particularly suitable foruse in the present invention.

Palm fatty acid distillate is a commercial product produced bydistilling off in vacuo the fatty acids present in natural palm oil.Typically it contains:

    ______________________________________                                        Free fatty acids 60-90%, usually 70-80%,                                                       by weight                                                    Water            <1% by weight                                                Triglycerides    10-40%, usually 20-30%                                                        by weight                                                    Unsaponifiables  less than 3% by weight                                       ______________________________________                                    

The iodine value is less than 54 and the melting point is 40° to 47° C.,usually about 45° C. The content of peroxides is below 10milliequivalents of oxygen per kilogram. The fatty acids in the freefatty acids and the triglycerides typically consist of

    ______________________________________                                        Palmitic acid      38-45% by weight                                           Oleic acid         37-42% by weight                                           Linoleic acid      8-10% by weight                                            Stearic acid       3-5% by weight                                             ______________________________________                                    

plus trace amounts of lauric, myristic, and linolenic acids.

Beef tallow acids, which are available commercially as a by-productobtained by alkaline extraction of waste beef fat and subsequentacidification, are also suitable for use in the present invention. Theytypically contain

    ______________________________________                                        Free fatty acids   60-90% preferably                                                             70-80%, by weight                                          Triglycerides      10-40%, preferably                                                            20-30%, by weight                                          Water              <1% by weight                                              Unsaponifiables    <3% by weight                                              ______________________________________                                    

The iodine value is less than 50 and the melting point is 40°-45° C. Thecontent of peroxides is less than 10 milliequivalents of oxygen perkilogram. The fatty acids in the free fatty acids and in thetriglycerides typically consist of

    ______________________________________                                        Palmitic acid      22-28% by weight                                           Oleic acid         38-44% by weight                                           Linoleic acid      3-6% by weight                                             Stearic acid       18-24% by weight                                           ______________________________________                                    

plus trace amounts of lauric, myristic and linolenic acids.

Hog fat acids and mutton tallow acids can also be used.

To protect the finished product from atmospheric oxidation it isnecessary, or at least desirable, to incorporate an anti-oxidant in thehigher fatty acids and corresponding triglycerides. This is especiallythe case where unsaturated fatty acids are present. It is thereforepreferred to use in manufacturing the feedstuff a mixture of fatty acidsand triglycerides having an iodine value less than 60 and a peroxidecontent (value) less than 10 milliequivalents of oxygen per kg, and toincorporate in the feedstuff a permitted oil-soluble antioxidant (i.e.an antioxidant permitted by the Food and Drug Administration forinclusion in animal feeds) and a permitted chelating agent to bind anyferric, copper, zinc or other transition metal ions capable ofcatalysing atmospheric oxidation which may be present. The antioxidant,which is preferably butylated hydroxy-toluene, is preferably added in anamount sufficient to suppress peroxide formation on exposure of thefeedstuff to air. The chelating agent, preferably citric acid, is addedin amount sufficient to bind the metal ions likely to be present andthus prevent them from catalysing oxidation of the fatty acids. Suitableproportions are 0.025-0.075%, preferably 0.05%, butylatedhydroxy-toluene or other antioxidant and 0.05-0.25%, preferably 0.15%,citric acid, or other chelating agent, based on the weight of the acidoil. To ensure homogenous mixing, the chelating agent is preferablyfirst dissolved in a small quantity (e.g. an equal weight) of an ediblesolvent which is miscible with the acid oil, e.g. propylene glycol, andthe solution is added to the acid oil before the process. Theant-oxidant is normally oil-soluble and presents no mixing problem.

Calcium oxide is the preferred basic oxide for use in the new process,but other basic oxides which are non-toxic and form water-insolublefatty acid salts, and in particular magnesium oxide, can in principle beused. Burnt (calcined) limestone is a suitable commercial source oflime. It usually contains 94-96% CaO and not more than 7% (usually 3 to5%) of CaCO₃. It should preferably have a particle size such that 99%passes a 150μ mesh for easy mixing with the other starting materials. Aspecial grade of commercial product is usually satisfactory in thisrespect. Calcined magnesite is a suitable source of magnesium oxide. Ifdesired calcium oxide and magnesium oxide can be used in admixture.

In one way of operating the new process, the fatty acid and thenon-toxic basic oxide are first rapidly mixed, and water is added. It isalso possible to mix all the ingredients simultaneously.

A third possibility is to mix the fatty acids and triglycerides with thewater and then to add the mixture to the basic oxide. It is alsopossible to mix part of the fatty acids and triglycerides with the waterand the remainder of the fatty acids and triglycerides with the basicoxide, and then to combine the two mixtures.

Preferably, the fatty acid is preheated, e.g. to 80°-100° C., preferably95° C., and then thoroughly mixed with lime. After the addition ofwater, there is a short induction period, and then a rapid reactionoccurs between the oxide, the water, and the fatty acid. This reactionis sufficiently exothermic to raise the temperature of the mixture toover 100° C. under normal conditions. The mixture should be rapidlyspread out, preferably on a moving continuous conveyor belt, and at atemperature of about 70° C., before substantial reaction takes place.The steam formed in the reaction is rapidly dispersed while the productis on the conveyor belt. A friable, easy to handle product is thusrapidly and conveniently obtained.

If any proteinaceous or other nutritional material is used, it is likelyto contain a small proportion of water even though it appears to be"dry". The presence of such small amounts of water should be taken intoaccount in forming the initial mixture but drying of these startingmaterials is not normally required.

The amount of water added is sufficient to permit rapid reaction betweenthe fatty acid and the calcium (or other) oxide but not so great as tocause any problem or unnecessary expenditure of energy in subsequentlyremoving it to give a dry product. It may sometimes be advantageous toadd the required water in the form of liquid water preheated to near theboiling point, e.g. to 90° C., but usually water at ambient temperatureis satisfactory. As stated above, the fatty acid is preferably hot whenadded to the mixture. Under normal conditions, the calcium oxide and thefatty acid react with sufficient generation of heat to raise thetemperature sufficiently so that when the product is spread outevaporation takes place and a dry product is easily and rapidlyobtained.

The proportions of the starting materials are chosen so that the productobtained shall have the desired nutritional composition and also therequisite physical properties. The proportion of the basic oxide used israther more than the stoichiometric amount calculated to react with thetotal fatty acids present. The feedstuff product should contain about 9to 15% by weight of the edible metal oxide, usually calcium oxide or,less preferably, magnesium oxide, as determined by calcination of theproduct at 850° C. Use of up to about an 80% excess of the lime or otherbasic oxide, over the stoichiometric amount, assures that this resultshall be obtained. With the preferred palm acid oil, this is equivalentto using 10 to 15%, and preferably about 12-13%, of calcium oxide basedon the combined weight of the palm acid oil and the oxide.

The proportion of water added is preferably the minimum amountconsistent with securing rapid and complete reaction between the fattyacids and the basic oxide. For example, when the fatty acids are palmacid oil (containing about 75% of fatty acids consisting mainly ofpalmitic acid, oleic acid and linoleic acid), and the basic oxide iscalcium oxide, then it is preferred to use one part by weight of calciumoxide to 7.0 parts by weight of the acid oil. The amount of water thenadded may be 15-25% and preferably about 18% by weight of the totalweight of the acid oil.

When nutritional material is used, a satisfactory product is usuallyobtained if the fatty acids and triglycerides and the nutritionalmaterial are used in approximately equal weights, for example from35-60% of fatty acids and triglycerides to 65-40% of nutritionalmaterial. Preferably, if the nutritional material is defatted soya beanmeal (containing not more than 2% of fat and 7-8% of water), theproportion used may be about 8 parts by weight to each seven parts byweight of the acid oil.

The process of the present invention is operated continuously. Thus thecalcium oxide (and soya meal or other nutritional material if present)may be mixed with the acid oil and the water and the mixture, beforesubstantial reaction takes place, is fed rapidly through a nozzle onto amoving belt on which the reaction proceeds to completion. Thetemperature of the reacting mixture on the belt is in the range100°-110° C., and most of the water present is boiled off while themixture is on the belt. The latter is made long enough to allow themixture to cool substantially and become converted into a dry friableproduct before it is sized, sieved and bagged. Cooling may, if desired,be hastened by blowing cool air over the mixture on the belt.

It is an advantage of the process that when ground whole soya bean isincorporated in the feedstuff as an additional nutritional material, thetrypsin inhibitor present therein is substantially destroyed by the heatevolved during the process.

The invention includes within its scope apparatus for carrying out theprocess of the invention comprising means for continuously supplyingmeasured amounts of said mixture of fatty acids and triglyceride, meansfor continuously supplying measured amounts of said basic oxide, andmeans for continuously supplying measured amounts of water; one or moremixing pump means for continuously mixing said fatty acids andtriglycerides, said basic oxide and said water; one or more conveyorbelts for receiving the mixture from said pump or pumps arranged topermit the mixture to react thereon; sizing means for adjusting the sizeof the reacted product; and means for collecting said product.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a preferred apparatus constructed inaccordance with the invention for carrying out the process.

FIG. 2 is a cross-sectional view of a conveyor belt used in theapparatus of FIG. 1.

FIG. 3 is a fragmentary perspective view of an alternative arrangementof the conveyor belt of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred apparatus for operating the process of the present inventionis shown diagrammatically in FIG. 1 of the accompanying drawings. InFIG. 1, calcium oxide (lime) from the hopper 1, and hot palm fatty aciddistillate or other acid oil (at e.g. 96° C.) from line 2 are mixed inpredetermined proportions in the mixing pump 3. Water at ambienttemperature is added through line 4. The mixture of starting materials,usually at about 65° C., is fed through mixing pumps 5 and 6 and rapidlydischarged as a semi-liquid reacting mass at about 100° C. on to thecontinuously moving conveyor belt 7 as a layer 8. A liquid retaining box9 is provided to keep the reacting mixture while it is still liquid fromspilling over the edges of the conveyor belt. The latter has a concavecross-section as shown in FIG. 2. Steam is evolved from the mixturewhile it is on the belt. At the end of belt 7 lumps of the product fallthrough a sizing (crumbling) machine 10 onto a second continuousconveyor belt 11 to form a layer 12. In this layer the reaction and thedrying are completed.

From the belt 11, the now essentially dry product falls into the sifter13 from which it is collected in appropriate bags for transportation andstorage.

Accurate metering of liquid and solid components is desirable. With theliquid reagents (the acid oil and water), this is conveniently achievedby using a constant head device feeding the liquid through a fixedorifice of appropriate size.

An alternative arrangement for the conveyor belt is showndiagrammatically in FIG. 3. In this arrangement the belt 7 carrying thereacting mass 8 is supported by low pressure air (or other gas) fed inthrough holes 14 as it moves over a curved plate 15 which defines thecross-sectional configuration of the belt. This configuration makes iteasier to control the temperature of the reacting mass (by controllingthe temperature of the air fed in through holes 14) and causes less wearon the belt.

The apparatus can readily produce one tonne or more per hour of baggedproduct containing less than 5% by weight of water.

Under typical conditions, the mixture of calcium oxide, fatty acids andtriglycerides, and water, can be formed, thoroughly mixed and dischargedon to the first conveyor belt 7 in not more than 10 to 20 seconds, andtimes as short as 2 seconds have been achieved. When the process isfirst started, visible reaction of the lime with the acid oil beginswithin about 45 seconds, but in steady conditions, the mixture in theliquid retaining box 9 is visibly reacting as the fresh mixture isdischarged by pump 6 into the box. The residence time on the first belt,which may be for example three to six feet (1 to 2 m,) preferably aboutfour feet (120 cm.), in width, is typically about 30 minutes, and thevisible reaction lasts for about half this period. At the end of thefirst belt the product has a dry appearance and is at a temperature ofabout 95° C. It is then easily crumbled in the sizing machine 10 whichhas only a low power consumption. The crumbled product, now is about 65°to 70° C., then falls on to the belt 11 on which it may be cooled by astream of cold air which also assists in the drying. Total overall timefrom mixing to bagging may be about 21/2 to 3 hours.

The bagged product typically has a total fatty acid content, as calciumsalt and free triglyceride, of about 85% by weight, a water content ofabout 3-5%, and a calcium content of 8 to 10% by weight (calculated asCa), together with small but important amounts of the butylatedhydroxy-toluene and citric acid already mentioned. The ash content,determined by calcining at 850° C., is not more than 15%, usually about12.5%, by weight.

The initially formed mixture containing fatty acid, calcium and water isvery sticky and it is important that the pumps 3, 5 and 6 areconstructed so as to be able to handle the mixture without clogging orthe need for frequent cleaning. Centrifugal pumps have been used withtheir impellers constructed so as to fit very closely the internalsurface of the pump housing. This produces a self-cleaning action in thepump which can operate for several days without any stoppages forcleaning being required.

It is a simple matter, if desired, to include a separate nutritionalmaterial in the process described above so that, in the final product,the calcium (or other) salt of the fatty acid impregnates thenutritional material.

Some feedstuffs, especially liquid feedstuffs containing a substantialamount of water, e.g. whey, may be added in controlled amount to themixture as it is discharged on to the belt 7. The heat of reaction issufficient to dry substantial proportions of such feedstuffs.

I claim:
 1. Apparatus for carrying out a continuous process for theproduction of a ruminant feedstuff which process comprises continuouslyforming a mixture of(1) one or more edible, saturated or unsaturatedfatty acids containing 14, 16 and/or 18 carbon atoms each, with not morethan minor amounts of fatty acids containing 12 and/or 20 carbon atomseach, the said fatty acid or fatty acids having an iodine value of lessthan about 60 and a melting point of at least 30° C., and being mixedwith triglycerides of said fatty acids and unsaponifiable material inthe proportions of 60% to 90% by weight of said acids, 40% to 10% byweight of said triglycerides and less than 3% by weight ofunsaponifiables; (2) one or more edible basic oxides capable of formingedible, water-insoluble salts with said fatty acids, the weight of thesaid oxide (2) being from 20% to 80% in excess of the weight equivalentof the total fatty acids; and (3) water in a proportion of 10% to 30% byweight of said fatty acids and triglycerides (1); homogenizing saidmixture before substantial chemical reaction takes place, continuouslyspreading out said mixtiure at above 60° C. and allowing said mixture toreact exothermically to form water-insoluble salts of said fatty acids;and continuously maintaining the reacting mixture in a spread-outconfiguration until it has cooled to below 70° C. and sufficient waterhas evaporated to give a friable product; said apparatus comprising:means for continuously supplying measured amounts of said mixture offatty acids and triglycerides, means for continuously supplying measuredamounts of said basic oxide, and means for continuously supplyingmeasured amounts of water; one or more mixing pump means forcontinuously mixing said fatty acids and triglycerides, said basic oxideand said water; one or more conveyor belts for receiving the mixturefrom said pump or pumps and arranged to permit the mixture to reactthereon; sizing means for adjusting the size of the reaction product;and means for collecting said product.
 2. Apparatus for carrying out acontinuous process for the production of a ruminant feedstuff whichprocess comprises continuously forming a mixture of one or more edible,saturated or unsaturated fatty acids and triglycerides thereof, one ormore edible basic oxides capable of forming edible, water-insolublesalts with the fatty acids, and water in a proportion of 10% to 30% byweight of said fatty acids and triglycerides; said apparatuscomprising:means for continuously supplying measured amounts of saidmixture of fatty acids and triglycerides, means for continuouslysupplying measured amounts of said basic oxide, and means forcontinuously supplying measured amounts of water; mixing means forcontinuously mixing said fatty acids and triglycerides, said basic oxideand said water; conveyor means for receiving the mixture from saidmixing means and arranged to support the mixture and permit the mixtureto react thereon to form a reaction product; sizing means for adjustingthe size of the reaction product; and means for collecting said reactionproduct.